Lamp receptacle



Feb. 14, 1933. L, v. LEWIS 1,897,668

LAMP RECEPTAGLE Filed 0G13. 9, 1929 INVENTOR I i which receive two screws 8 (Figs. 3 and 5).

Patented Feb. 14, 1933 UNITED STATES ATENT FFICE LLOYD V. LEWIS, OF EDGEWOOD BOROUGH, PENNSYLVANIA, ASSIGNOR TO THE UNION SWITCH t SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION 0F PENNSYLVANIA LAMP RECEPTACLE Application lled October- 9, 1929.

My invention relates to lamp receptacles, and particularly to lamp receptacles for switchboard lamps of the type commonly used in telephone switchboards and the like.

I will describe one form oli' lamp receptacle embodying my invention, and will then point out'the novel features thereofin claims.

In the accompanying drawing, Fig. l 1s a view showing, in side elevation, one form of lamp receptacle embodying my invention'attached to a control panel. Fig. 2 1s an isometric view of the body l of the receptacle shown in Fig. l. Fig. 3 is a sectional view on the line III- III of Fig. l. Fig. l is an end view of the receptacle shown in Figs. l and 3 as it appears when viewed from the right in Fig. 8. Fig. 5 is a sectional view similar to Fig. 3 but showing a lampand lamp cap in place in the receptacle. Fig. 6 is an end view of the bushing for attaching the receptacle to the panel.

Similar reference characters refer to s1m ilar parts in each of the several views.

Referring lirst to Figs. l and 2, the receptacle, designated, in general, by the reference character A, comprises a body l of suitable insulating material such, for example, as balielite. This body l, in the form here shown, 1s construct-ed with a circular end portion l, a hat end portion lb which is substantially rectangular in cross-section, and. an intermediate portion lC which is tapered 1n such manner that the flat surfaces of the end portion lb gradually merge into the rounded surface of the end portion la.

The end portion la is provided with an axial opening lg which communicates with a rectangular slot ld passing through the intermediate portion lc from one side to the other. The outer end of the opening lg has a larger diameter than the inner end of the opening, as best shown in Fig. 3, and is threaded to receive a bushing 2 having an annular flange 2 by means of which the receptacle A may be attached to a switchboard or control panel indicated at 3 in the drawing.

The end portion lb of the body l is provided with two holes le and lf (see Fig. 2) I and 9, respectively Mounted on the screws 8 Serial ITo. 398,333.

and 9 on opposite sides of the end portion lb, and clamped in place by a plate 7 into which the screws 8 and 9 are threaded, are two resilient contact lingers 4 andl 5. The contact lingers e and 5 are insulated from the screws 8 and 9 by insulating sleeves l2, l3 which surround the screws, and by two insulating blocks l and ll which are interposed respectively between the heads of the screws and the contact linger 4l and between the plate 7 and the contact linger 5. A plate 6, interposed between the heads of the screws and the insulating block l0, distributes over a large area the pressure which the heads of the screws exert on the block l0 when the screws are tightened, and prevents the heads of the screws from cutting into the block l0. The left-hand end of each contact linger is tapered as seen in F ig. l, and the tapered end of the finger et is crimped at 4a and 4b to form projections which extend into the slot ld near its opposite ends, while the tapered end of the linger is similarly crimped at 5a and 51 to form projections which extend into the slot l1 opposite the corresponding projections in the linger e. The tip of the tapered end of the linger i is provided with an olfset extension 4c which extends past the left hand edge of the slot ld and the tip of the tapered end of 'the fingere is provided with a similar offset extension 5C. lWhen the receptacle A is empty, as shown in Fig. 3, the oliset extensions 4C and 5C engage the body l adjacent the end of the slot ld and prevent the fingers from being pressed together to cause a short circuit. The right-hand end of the contact linger 4 is provided with a hole 4d to facilitate making a soldered connection thereto, and the linger 5 is provided with a similar hole 5d.

The bushing 2, in addition to providing means for attaching the receptacle to a switchboard, or control panel, also serves as a holder for a lamp cap l5 as best seen in Fig. 5. rThe lamp cap l5 is a standard cap of the well known t-ype commonly employed in telephone switchboards and comprises a metal tube l5c having a bezel ring 15b formed on one end and having the other end slotted to form resilient seg-ments which are crimped to form an annular bead 15d. The bezel ring 15b carries the usual bulls eye 15a which may have any appropriate color as desired. For co-operation with the lamp cap 15, the inside of the bushing 2 is provided with an annular projection 2d, the outer edge 2e of which is normal to the axis of the bushing, and the inner edge 2C of which is beveled, as best seen in Fig. 3. lVhen the lamp cap 15 is inserted in the bushing 2, the edge 2e of the projection 2d engages the cap at the righthand end of the bezel ring 15b as viewed in Fig. 5 and acts as a stop, while the beveled edge 2c of the projection 2d engages the cap 15 at the annular bead 15I and holds the cap in place. To facilitate removing the lamp cap, and to permit the use of a screw driver for attaching the receptacle to the panel, the bushing 2 is also provided with a saw kerf 2" as best seen in Figs. 3 and 6.

The receptacle A is particularly adapted to receive a standard telephone switchboard lamp such as the lamp 14 illustrated in Fig. 5. This lamp, in the form here shown, comprises a wedge-shaped base 14b of insulating material carrying two diametrically opposite spaced terminals 14c between which is secured a small tubular bulb 14;L containing a filament 14d. The lamp 14 may be inserted in the receptacle A through the bushing 2 by removing the lamp cap 15. Vhen the lamp is being inserted in the receptacle, the projections 4"L and 5EL engage the wedge-shaped base 14b of the lamp 14 as the base moves past these projections and automatically turn the lamp to the position in which the terminals 14C are in alignment with the projections 4a and 5a. In case the lamp is turned from the position in which the terminals 14c are n.in alignment with the projections 4EL and 5a Aaft-er the base of the lamp has moved past the projections 4a and 5a, however, the pro jections 4b and 5b are so arranged that these projections will then engage the base and either restore the lamp to the proper position as the lamp is moved the rest of the Way into the receptacle, or else prevent the lamp from being inserted into the receptacle fai' enough to permit the lamp cap to be replaced,

- thus insuring that the lamp will be inserted `in the receptacle in the proper position.

When the lamp is inserted in the receptacle inthe proper position, the projections 4a and 5a engage the terminals 14C of the lamp and make electrical contact therewith. The

width of the tapered end of each finger is made narrower than the distance between the terminals 14c of the lamp 14 so that it is iinpossible for the contact fingers to bridge the terminals of the lamp under any condition and cause a short circuit. Furthermore, the distance between the projections 4aM and 5a and the inner end of the bushing 2 is suliiciently large so that when a lamp is being inserted in the receptacle A, the terminals 14C will have passed the bushing 2 before the terminals engage the contact fingers at the projections 4a and 5a. It is therefore impossible for a linger 4 or 5 to be connected with the bushing 2 by a terminal 14c during insertion of the lamp.

One advantage of a receptacle embodying my invention is that due to the construction and arrangement of the parts the risk of short circuits in replacing lamps is completely eliminated. Y

Another advantage of a. receptacle embodying my invention is that the receptacle may be attached directly to a metal control panel or switchboard without insulating the re ceptacle from the panel or switchboard by drilling a single hole in the panel.

Another advantage is that due to the ab! sence of attachment lugs or projecting parts several lamp receptacles may be located very close together, because the diameter of the parts at the rear of the panel is substantially the same as the outside diameter of the bushing at the front of the panel.

Another advantage is that by use of suitable lamp replacing tools, the lamp may be removed and replaced from the front of the panel, so that it is unnecessary to give the operator access to the rear of the panel, and risk of disturbing wiring or connections is avoided.

Still another advantage of my invention is that the factor of safety against insulation breakdown is extremely high.

Although I have herein shown and described only one form of lamp receptacle embodying my invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

1. A receptacle for cooperation with a telephone switchboard lamp of the type com prising a tubular bulb secured between diametrically opposite spaced terminals carried by a wedge-shaped base of insulating material, said receptacle comprising a body of insulating material having a circular portion at one end provided with an opening for receiving said lamp and having a rectangular portion at the other end provided with two spaced holes extending therethrough from one side to the other and having an intermediate tapered portion provided with a rectangular slot extending therethrough from one side to the other and Communicating at between the spaced terminals of said lamp and said fingers having their tapered ends crimped to form two pairs of spaced projections which extend into said slot and each nger having the tip of the taper-ed portion provided with an offset extension which projects past the end of said slot, one pair of projections being disposed opposite each other near one end of said slot in a position to engage the trniinals of said lamp and make electrica-l connection therewith and said second projections being disposed opposite each other near the other end of said slot in such manner that said lamp is prevented from being inserted completely into said receptacle unless said terminals are in alignment with said first projections, a first metal plate threaded to receive said screws for clamping said fingers in place, two blocks of insulating material one interposed between one contact finger and the heads of said screws and the other interposed between the other Enger and said plate, and a plate interposed between the heads of said screws and the adjacent block of insulating material.

2. A receptacle for a standard telephone switchboard lamp of the type comprising a tubular bulb secured between diametrically opposite spaced terminals carried by a wedge-shaped base of insulating material, said receptacle comprising a body of insulating material provided with an opening for receiving said lamp, and two contact lingers attached to said body, each said finger having one end tapered to a width which is less than the distance between the spaced terminals of said lamp and said iingers having their tapered ends crimped to form two pairs of projections, one pair of projections being disposed in a position to engage the terminals of said lamp when said lamp is inserted into said receptacle and make electrical connection with said terminals, and the other pair of projections being disposed in such manner that said lamp is prevented from being fully inserted into said receptacle unless said terminals are in alignment with said one pair of projections.

3. A receptacle for a standard telephone switchboard lamp of the type comprising a tubular bulb secured bet-Ween diametrically opposite spaced terminals carried by a wedge shaped base of insulating material, said receptacle comprising a body of insulating material provided with an opening for receiving said lamp, and two contact fingers attached to said body and each having a portion which is narrower than the distance be tween the terminals of said lamp and another portion which is substantially as wide as the base of said lamp, the narrow portions of said lingers being crimped to form one pair of projections and the wide portions being crimped to form another pair of projections, said one pair of projections being disposed opposite each other in a position to engage the terminals of said lamp and make electrical contact therewith, and said other pair of projections being disposed opposite each other in such manner that when said lamp is inserted in said receptacle in approximately the correct position :for said one pair of projections to engage the terminals of said lamp said other pair of projections will engage said wedge shaped base and will turn said lamp to the exact positionfor said projections to engage said terminals.

a. A receptacle for a standard telephone switchboard lamp of the type comprising a tubular bulb secured between diametrically opposite spaced terminals carried by a wedge shaped base of insulating material, said receptacle comprising a body of insulating material provided with an opening for receiving said lamp, and two contact lingers attached to said body and each having a portion which is narrower than the distance between the terminals of said lamp and another portion which is substantially as wide as the base of said lamp, the narrow portions of said fingers being crimped to from one pair or" projections and the wide portions being crimped to form another pair of projections, said one pair of projections being disposed opposite each other in a position to engage the terminals of said lamp and make electrical contact therewith, and said other pair of projections being disposed opposite each other in such manner that when said lamp is inserted in said receptacle in approximately the correct position for said one pair of projections to engage the terminals of said lamp said other pair of projections will engage said wedge shaped base and will turn said lamp to the exact position for said projections to engage said terminals, said fingers further being provided with oiset portions which cooperate with said body to prevent said lingers from being pressed together when said receptacle is empty.

In testimony whereof I aiiiX my signature.

LLOYD v. Lnwis. 

